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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>

        var arr = ["hello"];
        //arr[1] = "大家好";
        //push() 方法的返回值是添加元素后数组的新长度。
        var mylength = arr.push("大家好","world",100,true);

        console.log(arr);
        console.log(mylength);

        var arr1 = [100,200,300,400];
        var popp = arr1.pop();

        console.log(popp);
        console.log(arr1);



    </script>
</body>
</html>